Apparatus for determining the contour of interior surfaces of workpieces



Oct. 19, 1954 w. RINKER 2,691,837

APPARATUS FOR DETERMINING THE CQNTOUR OF INTERIOR SURFACES OF WORKPIECES Filed Nov. 16, 1951 2 Sheets-Sheet l Tic]- l- IN V EN TOR. i

BY main} QTTOPNEY Oct. 19, 1954 w. RINKER 2,691,887

APPARATUS FOR DETERMINING THE CONTOUR OF INTERIOR SURFACES OF WORKPIECES Filed Nov. 16, 1951 2 Sheets-Sheet 2 JNVENTOR.

BY M

Patented Oct. 19, 1954 APPARATUS FOR DETERMINING THE CON- TOUR F INTERIOR SURFACES OF WORK- PIECES Wilhelm Rinker, Wetzlar, Germany, assignor to Ernst Leitz, G. m. b. H., Wetzlar, Germany, a corporation of Germany Application November 16, 1951, Serial No. 256,694

2 Claims. 1

My present invention relates to apparatus for testing the contours of a surface, that is, the roughness or the presence of depressions or of raised portions in the interior surface of a work piece.

Testing apparatus for investigating the surfaces of work pieces have been known, whose testing or probing needle has been subjected to swinging so that the needle follows precisely the slightest unevenness of the surface as, for example, in German Patent No. 740,781.

this possible.

vention, and,

part of the apparatus of Fig. l.

on a table II.

spring 4 1.

(Cl. 73-1ll5) the head I to whose free end is secured a weak leaf spring 5 which forms the fulcrum of a double arm lever 6. To one end of this lever B is secured a test probe 7 which probes the inner surface it of a tube It which is mounted on a control slide 20. The other end of the lever is joined with the transmission pin 2 by a leaf spring 8, the pin being guided by a holder 9. The transmission pin 2 has a collar 2 I on which a double arm lever 22 lo acts, which lever is rockable about an axis 223 With the apparatus and set into vibration by an electromagnet 25, the heretofore known the inner surfaces, for example, core of which is a permanent magnet, iii-circuit borings, of work pieces could not be tested. My with an alternating current source it. invention relates to an apparatus which renders Upon passing an alternating current through the electromagnet 25 one end of the lever 22 is at- In my invention a double arm lever is mounted tracted in one phase so that the transmission pin by a weak spring as a fulcrum so that the reso- 2 can sink until the test probe 1! rests on the surnance of swinging of the lever system lies below face I8. Correspondingly when this end of the the frequency of an imposed swinging which is swinging lever l3 sinks under the tension of the imparted to the system from a transmission pin Sp i g 3 t light Source is reflected to a CONE- set into vibration and joined to an end of the p md g po t 0 e Scale H which corresponds lever by a spring, preferably a leaf spring. The with the position of rest of the test probe i on leaf spring which joins the transmission pin to the surface #8. In the second phase of the alterthe lever is rigid in the direction of transmission. natins rr nt h fr e nd f the lever it falls At the other end of the lever is mounted a test 25 away from. the electromag 5 d the t e probe or needle which probes the contour of the 8 d o t e lever St up y Oh t e 0011M surface to be tested and whose deflection, de- 1 0f the transmission P 2 and lifts it d pendent on the surface contour, is transmitted cordin y frees the test Probe O the Surface through the lever, the leaf spring and the trans- It. l he frequency of oscillation which is in this mission pin to an indicating apparatus, 3 manner imposed on the transmission pin in the The oscillation of the transmission pin is direction of the arrow 3 is equal to the frequ y actuated in an suitable kno n ma for of the alternating current while the natural resoample, electromechanically and is for this purmint swinging f e l v r y m t i i lly pose above the resonant vibration of the lever lower. system in order not to bring about a vibration of The P mane magnet core f he electromagtoo great an amplitude by setting up resonance haS north p and a South P r effects, which through the test probe would have ample, the pp B being h d the lower a tendency to impair the surface being tested. pole being u The alternating current c- An embodiment of the invention is illustrated by p d from t e alternating Source e forces the way of example in the accompanying drawings, in so polarity when the current is pass in one direcwhich Fig. 1 is an elevation partly in section of tion and nullifies it when the current is passing apparatus embodying a preferred form of my inin the opposite direction to provide cycles in which the magnet attracts and releases the lever Fig. 2 is a vertical section on a larger scale of The same result could be obtained by means of a rectifier in one of the leads to the electromagnet. In the accompanylng wings there is shown The apparatus of the above invention is parway of example an embodiment of the i ticularly suited for use as a surface tester of the non inwhlch ahead I of th Su a Contour test" described type as well as for interior testing of mg apparatus is mounted on a pillar It mounted a11kinds 2 to one end {2 1 ;22 :35 gigg ggg fi g gg ggg Having described my invention, what I claim is: at y it d t h 1 p Apparatus Ior testing surfaces which com- 15 we enslonal y e dbyeienswn pr1ses a double arm lever, a leaf spring fulcrum f? me free end P the level for said lever, a test probe mounted on one end of i3 amirror it is mounted which reflects light from Said 1ever, a leaf spring mounted on the uther a source it to a scale H. An arm 4 is secured to end of said lever and extending in the direction.

of movement of said end about the fulcrum of said lever, a transmission pin secured to said leaf spring in alignment therewith, means to oscillate said transmission pin longitudinally With a frequency independent of that of said double arm lever, and means responsive to movement of said transmission pin to indicate the amplitude of oscillation thereof.

2. The apparatus of claim 1 in Which said means for indicating the amplitude of oscillation of said transmission pin comprises a light source, a scale, and a mirror tiltable by said transmission pin to reflect light from said source onto said scale.

4 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 96,383 Moore Mar, 12, 1946 FOREIGN PATENTS Number Country Date 118,097 Australia July 3, 1942 OTHER REFERENCES Methods of Measurement and Definition of Surfaces, H. Becker in Microtecnic, vol. IV, No. pp. 302-307, November-December 1950. 

